The present invention relates to a method and apparatus for a cleaning treatment in a system, in which, for example, substrates used for a liquid crystal display (hereafter referred to as LCD) and a semiconductor device are treated.
Recently, it has become an urgent need in apparatuses for various kinds treatment, for example in a resist coater which is used to form a resist film on a LCD substrate, that the size of an apparatus itself is reduced, the production cost is decreased and in addition a running cost of the apparatus is decreased.
In a resist coater generally used in a fabrication process of LCD, treatments of resist coating and cleaning are given on a glass substrate (an object to be treated), and there are two kinds of resist coater, which are of types of spin-coating and spray-coating.
A resist coater of a spin-coating type comprises, for example: a spin chuck, on which a glass substrate is mounted, and which is free to be shiftable vertically while being free to be rotatable; a resist solution instillator which supplies a resist liquid in the middle potion of the substrate drop by drop; a jet nozzle of a cleaning liquid to clean the surface of the substrate; and a rotary cup and a drainage cup being disposed outside the substrate in a manner doubly surrounding the substrate, wherein the rotary cup is inside the stationary cup and the rotary cup receives the resist liquid or a thinner flowing out or flying out from the substrate.
In such a resist coater, a glass substrate is mounted on a spin chuck which is free to be shiftable vertically while being free to be rotatable and a resist liquid is supplied to the middle portion of the substrate drop by drop while rotating the substrate to form a uniform resist film by a centrifugal force. In the case, a residue of the resist liquid which flows out or flies out from the substrate is received by the rotary cup to be discharged. In a following step, a height of the spin chuck is changed and a cleaning liquid is supplied from the cleaning liquid jet nozzle to the edge of the substrate to clean the edge portion of both surfaces of the substrate and a waste liquid is received by the drainage cup to be discharged. As a cleaning liquid, a solvent such as a thinner is used, since it is less in pollution and higher in safety.
In the same resist coater, since a used cleaning liquid (a waste liquid) has a lot of a resist ingredient dissolved therein, the used cleaning liquid cannot be reused on the substrate and is stored in a waste liquid storage unit through a waste liquid pipe. The waste liquid stored in the storage unit is wasted when it is accumulated to some extent.
In the drainage cup, since a thinner constantly including a resist ingredient is fed, the resist ingredient is piled up as a deposit on the inner wall of the cup in a adhered manner. When the resist ingredient is adhered and piled up to some extent, clogging will be caused, the inner wall of the drainage cup has been conventionally cleaned at an interval and the deposit has been separated off. Such a situation is also applied to the case of the rotary cup which directly receive the used resist liquid itself.
However, in a conventional resist coater, a thinner is sprayed toward the inner surface of a cup from a nozzle exclusively used for cleaning the inside of the cup disposed in the cup in order to remove the deposit inside the cup and therefore a lot of the thinner is required.
As described above, there has been a problem in a conventional resist coater, which is an apparatus for a coating treatment, that contamination such as an resist is adhered on the inner wall of a cup when the treatment is repeated and such contamination requires a lot of the thinner to be removed, so that the expense for cleaning is accumulated.
Besides, a used cleaning liquid cannot be used in a cleaning treatment of a glass substrate to be cleaned and therefore the used cleaning liquid is wasted as a waste liquid, which has been another cause to increase a running cost.
While application of a resist liquid on the surface of an object to be treated such as a LCD substrate has been effected by a spin coating method, In the case, since a LCD substrate has a rectangular shape, which causes a turbulent flow in the air by rotation, there arises a problem that uniformity of a thickness of a resist film cannot be maintained.
For such a reason, conventionally a surrounding space above, under and near the sides of a spin chuck as a holding means for holding LCD substrate and a LCD substrate are enclosed by a rotary cup with a cover and a rectifying plate is disposed above the LCD substrate in the rotary cup with a cover and the air supplied through an air supply port formed in the cover of the rotary cup with a cover is rectified by the rectifying plate to be discharged through an exhaust port located at the bottom of the rotary cup. In such a manner, A disorder in thickness of a resist film by a turbulence in the air have been avoided. A stationary cup is so disposed as to enclose the side and lower portions of the covered cup in order to prevent an air stream created by rotation of the rotary cup from flowing back into the inside of the rotary cup.
However, in a resist coater in which a resist liquid is applied by a spin coating method of this kind, a resist solution is sprayed outwardly by an centrifugal force and therefore a resist is adhered on the inner side and the bottom of the rotary cup, back surface of the covered cup, and the lower surface of the rectifying plate and the like. Besides, there is a fear that the resist is adhered in the inner side and the bottom of the stationary cup. In such a manner, a resist adhered on the rotary cup, the inside of the stationary cup, on the cover, the rectifying plate and the like is dried to produce particles. If the particles are adhered on a LCD substrate, a difficulty occurs on a circuit patterning and the like and at the same time a problem of reduction in a yield is resulted.
It is an object of the present invention to provide a method and apparatus for a cleaning treatment, in which a cleaning liquid to be used for cleaning a treated object is effectively used.
It is a second object of the present invention to provide an apparatus for a treatment in which a cleaning solution is reused.
It is a third object of the present invention to provide an apparatus for a treatment in which a cleaning efficiency of a vessel can be achieved.
It is a fourth object of the present invention to provide an apparatus for a treatment in which a running cost of the whole apparatus can be reduced.
The fourth object of the present invention is to provide a method and apparatus for a cleaning treatment in which a coating liquid, such as a resist, adhered on a rotary cup and a stationary cup of a coating mechanism is removed to improve a yield.
In order to achieve the above mentioned objects, a method for a cleaning treatment of the present invention has a feature that the method comprises the steps of: cleaning a treated object is cleaned with a cleaning liquid supplied; then recovering the cleaning liquid; removing gas in the recovered cleaning liquid by separation; then storing the recovered liquid in a storing section; and reusing the stored cleaning liquid for cleaning an object to be treated.
In the method for a cleaning treatment, it is preferred that the stored cleaning liquid is used for cleaning the apparatus for a treatment for the object. Besides, it is also possible in a method for a cleaning treatment of the present invention that a cleaning liquid is additionally supplied to replenish the storing section for the recovered cleaning liquid with a cleaning liquid and a mixture of the added cleaning liquid and the recovered cleaning liquid is used for cleaning.
An apparatus for a cleaning treatment of the present invention comprises: first supply means for supplying a cleaning liquid to an object treated; a recovering pipe for recovering a cleaning liquid already used for cleaning of the object treated; gas/liquid separation means for separating gas from the recovered liquid by separation; a cleaning liquid storing section for storing the cleaning liquid separated by the gas/liquid separation means; and second cleaning liquid supply means for supplying the cleaning liquid in the cleaning storing section to an object o be cleaned.
In the apparatus for a cleaning treatment, it is preferred that the apparatus for a cleaning treatment further comprises second cleaning liquid supply means. In the same apparatus for a cleaning treatment of the present invention, the first cleaning liquid supply means has a plurality of nozzle holes for jetting a cleaning liquid toward positions, which do not interfere with each other, on both surfaces of peripheral portion of the treated object, and the recovering pipe is provided at a position outwardly and laterally of the nozzles. In the case, an opening of a route for a waste liquid which are connected to the recovering pipe at the other end preferably has a taper having the maximum diameter at the outermost end in order to effectively receive the cleaning liquid jetted from the nozzle holes. That is, it is preferred that the nozzle holes are located in the inside of the opening at the outermost end of the waste liquid route wherein the end portion has a taper and the diameter of the opening is the maximum in the tapered end portion. Moreover, the above mentioned cleaning liquid storing section can be preferably formed in such a manner that a cleaning liquid is directly supplemented from a cleaning liquid supply source.
According to the present invention, a cleaning liquid is supplied to an object to clean it, thereafter, the cleaning liquid is recovered, gas is separated and removed from the recovered liquid, then the recovered liquid is stored, the stored cleaning liquid is reused for cleaning of an object to be cleaned and thus the cleaning liquid can be effectively used. Accordingly, since a usage amount of the cleaning can be reduced, the cost is reduced and natural resources can be effectively used.
An efficiency of usage of a cleaning liquid in the same treatment system can be further increased by reusing a stored cleaning liquid for cleaning of an apparatus for a cleaning treatment, whereby a scale of the apparatus can be smaller, since the piping system of the cleaning liquid is simpler.
A cleaning efficiency is further increased by supplementing the storing section of the recovered cleaning liquid with the fresh cleaning liquid and using a liquid mixture of the supplementing cleaning liquid and recovered cleaning liquid for cleaning the object to be cleaned and a reliability of the apparatus for a cleaning apparatus can be improved. With the first cleaning supply means having nozzle holes to jet the cleaning liquid toward positions on both surface of a peripheral portion of the object treated at which streams of the cleaning liquid do not interfere with each other and with the recovering pipe provided at a position outwardly and laterally of the nozzle holes, since a cleaning liquid which is used in a first cleaning step and which is supplied from the first cleaning liquid supply means is recovered with a good efficiency, loss of the cleaning liquid is avoided and as a result a cleaning efficiency can be increased.
A second apparatus for a treatment of the present invention is directed to an apparatus comprising: a vessel for recovering a treatment liquid flowing out or flying out when an object is treated; cleaning means for cleaning the inner wall surface of the vessel by supplying a cleaning liquid into the vessel; and a circulating system for recovering a discharged liquid discharged from the vessel when the inner wall surface of the vessel is cleaned by the cleaning means and supplying it to the cleaning means.
In the second apparatus of the present invention, since the discharged liquid from the vessel when the inner wall surface of the vessel is cleaned by means of the cleaning means is recovered by the circulating system and supplied to the cleaning means which is used for cleaning the inside of the vessel, the cleaning liquid can be reused. Thereby, a usage volume of the cleaning liquid is reduced and at the same time the running cost of the whole apparatus can be reduced.
A third apparatus for a treatment of the present invention is directed to an apparatus defined as the second apparatus, wherein the circulating system comprises: a fresh cleaning liquid storing section for an unused cleaning liquid; a discharged liquid storing section for storing a discharged liquid discharged from the vessel; a cleaning liquid supply means for supplying the discharged liquid stored in the discharged liquid storing section and the unused cleaning liquid stored in the fresh cleaning liquid storing section, singly or in mixture, to the cleaning means.
In the third apparatus, since the discharged liquid stored in the discharged liquid storing section and the unused cleaning liquid stored in the fresh cleaning liquid storing section, singly or in mixture, are supplied to the cleaning means, no difficulty arises in cleaning a cup.
A fourth apparatus for a cleaning treatment of the present invention is directed to an apparatus defined as the second apparatus, wherein the circulating system comprises: a first discharged liquid storing section for storing a first discharged liquid collected and discharged to the vessel when at least part of the object already treated is cleaned; a second discharged liquid storing section for storing a second discharged liquid collected and discharged to the vessel when the inner wall surface of the vessel is cleaned; and a cleaning liquid supply means for supplying the first discharged liquid stored in the second discharged liquid storing section and the second discharged liquid stored in the second discharged liquid storing section, singly or in mixture, to the cleaning means.
In the fourth apparatus, since the first discharged liquid stored in the second discharged liquid storing section and the second discharged liquid stored in the second discharged liquid storing section, singly or in mixture, are supplied to the cleaning means, the once used cleaning liquid can be used with a good efficiency.
A fifth apparatus for a cleaning treatment of the present invention is directed to an apparatus defined as the fourth apparatus, wherein the cleaning liquid supply means supplies, for supplement, an unused cleaning liquid for cleaning at least part of the object already treated to at least one of the first discharge liquid storing section and the second discharge liquid storing section and supplies the stored liquids stored in the respective storing sections, single or in mixture, to the cleaning means.
In the fifth apparatus, since at least one of the first and second discharged liquid sections are supplemented with the unused cleaning liquid, that is a fresh cleaning liquid, to dilute the discharged liquids stored in the respective sections, and the discharged liquids, singly or in mixture, are supplied to the cleaning means, the once used cleaning liquid can be used without degrading a cleaning performance of the used cleaning liquid by any margin and the reuse of a cleaning liquid can be effected with a good efficiency.
A sixth apparatus of the present invention is directed to an apparatus defined as the second apparatus, wherein the circulating system comprises: a fresh liquid string section for storing an unused cleaning liquid; a first discharged liquid storing section for storing a first discharged liquid collected and discharged to the vessel when at least part of the object already treated is cleaned; a second discharged liquid storing section for storing a second discharged liquid collected and discharged to the vessel when the inner wall surface of the vessel is cleaned; and a cleaning liquid supply means for supplying the unused cleaning liquid stored in the fresh cleaning liquid storing section to at least one of the first discharged liquid storing section and the second discharged storing section and supplying to the cleaning means.
In the sixth apparatus, since the unused cleaning liquid stored in the fresh cleaning liquid storing section is added as supplement to at least one of the first and second discharged liquid sections and a discharged liquid from the at least one discharged liquid storing section supplemented with the unused cleaning liquid is supplied to the cleaning means, reuse of the cleaning liquid for cleaning a cup can be effected without any difficulty and without any degradation in a cleaning performance, so that a cleaning efficiency in cap cleaning is improved and a reliability of a cap cleaning operation is also increased.
A seventh apparatus of the present invention is directed to an apparatus defined as the second apparatus, wherein the circulating system comprises: a fresh cleaning liquid storing section for storing an unused cleaning liquid; a first discharged liquid storing section for storing a first discharged liquid collected and discharged to the vessel when at least part of the object already treated is cleaned; a second discharged liquid storing section for storing a second discharged liquid collected and discharged to the vessel when the inner wall surface of the vessel is cleaned; and a cleaning liquid supply means for supply the first discharged liquid stored in the first discharged liquid storing section, the second discharged liquid stored in the second discharged liquid storing section and the unused cleaning liquid stored in the fresh cleaning liquid storing section, singly of in mixture, to the cleaning means.
In the seventh apparatus, since the first discharged liquid stored in the first discharged liquid storing section, the second discharged liquid stored in the second discharged liquid storing section and the unused cleaning liquid stored in the fresh cleaning liquid storing section, singly of in mixture, are supplied to the cleaning means, the inside of the vessel can be cleaned with a good efficiency.
An eight apparatus of the present invention is directed to an apparatus defined as the third to seventh apparatus for a cleaning treatment, wherein the cleaning liquid supply means comprises: detecting means for detecting an amount of the cleaning liquid and discharged liquid stored in the respective storing sections; control means for controlling intake amounts of the cleaning liquid and discharged liquid based on the respective amounts detected by means of the detecting means.
In the eight apparatus, since the amounts of the cleaning liquid and discharged liquid stored in the respective storing sections are detected and the control means controls amounts of the cleaning liquid and discharged liquid which are fetched from the respective storing sections based on the amounts of the liquids detected by means of the detecting means, the amounts of the respective liquids being supplied to sections of the apparatus can be optimized.
A ninth apparatus of the present invention is directed to an apparatus defined as the third apparatus for a cleaning treatment, wherein the cleaning means comprises a first jetting unit for jetting the cleaning liquid toward the inner wall surface of the vessel in the vicinity of the object treated and a second jetting unit for jetting the cleaning liquid toward the inner wall surface in the vicinity of the discharge port remote from the object treated, and the circulating system supplies the discharged liquid, which is a used cleaning liquid, for the second jetting unit and the unused cleaning liquid for the first jetting unit.
In the ninth apparatus, since the discharged liquid, which is a used cleaning liquid, and the unused cleaning liquid are respectively to the second jetting unit and to the first jetting unit, the cleaning liquid can be used in the respective uses with a good efficiency.
A tenth apparatus of the present invention is directed to any of apparatuses defined as the first to ninth apparatuses, wherein the apparatus comprise a vessel for recovering a treatment liquid flowing out or flying out when the object is treated and the inner wall surface of the vessel has an ethylene fluoride based resin layer formed on the surface.
In the apparatuses, since the ethylene fluoride based resin layer is formed on the inner wall surface, the treatment liquid which flows out or flies out when the object is treated is less adhered.
An eleventh apparatus of the present invention is directed to any of apparatuses defined as the tenth apparatus, wherein the apparatus has an ethylene fluoride based resin layer formed on an inner surface of a recovering path inside the vessel in which the treatment liquid is recoverable.
In the eleventh apparatus, while part which is covered with an ethylene fluoride layer is limited, adhesion of the treatment liquid is minimized, so that, with a minimized usage amount of ethylene fluoride based resin, an effect that the reduced adhesion of the treatment liquid is achieved.
An aspect of the present invention is directed to an apparatus for a cleaning treatment of a cup in a coating mechanism, comprising: a rotary cup with a cover which is rotatable, and which encloses a holding means for holding an object treated and the side and bottom portions of the object to be treated; a stationary cup which encloses the side and bottom portions of the covered rotary cup; and a rectifying plate covering the object treated at a position thereabove, which is mounted inside the covered rotary cup, the apparatus comprising: a first nozzle for supplying a cleaning liquid on the rectifying plate by way of a supply hole bored in the middle of the cover of the covered rotary cup; a second nozzle, which is located under the holding means, for supplying the cleaning liquid toward the lower surface of the peripheral portion of the rectifying plate, the inner side surface of the covered rotary cup and the bottom surface of the stationary cup.
In the apparatus of the present invention, it is preferred that the apparatus further comprises a third nozzle, which is located inside the stationary cup, for supplying the cleaning liquid toward a lower part of the outside surface of the covered rotary cup and the inner side surface of the stationary cup. In this case, a lower part of the stationary cup is so formed that the inner surface is bent outwardly and the bottom is open and the cleaning liquid is supplied toward to the bent portion of the inner side surface of the stationary cup from the third nozzle.
An aspect of the present invention is directed to a method for a cleaning treatment of a cup in a coating mechanism comprising a rotary cup with a cover which is rotatable, and which encloses a holding means for holding an object treated and the side and bottom portions of the object treated; a stationary cup which encloses the side and bottom portions of the covered rotary cup; and a rectifying plate covering the object treated at a position thereabove, comprising the steps of: supplying a cleaning liquid through the middle of the cover of the covered rotary cup toward the rectifying plate while rotating the covered rotary cup to supply the cleaning liquid to the lower surface of the cover with the help of an centrifugal force; and at the same time supplying the cleaning liquid toward the lower surface of the outer periphery of the rectifying plate, the inner side surface of the covered rotary cup and the bottom surface of the stationary cup.
In the method of the present invention, it is preferred that the cleaning liquid is supplied on a lower part of the outside surface of the covered rotary cup and the inner side surface of the stationary cup.
In the method of the present invention, it is also preferred that the cleaning liquid is supplied toward the rectifying plate from the middle of the cover of the covered rotary cup, while rotating the covered rotary cup at a first rotational speed; the cleaning liquid is supplied toward the lower surface of the outer peripheral portion of the rectifying plate and the inner side surface of the covered rotary cup, while rotating the covered rotary cup at a second rotational speed larger than the first rotational speed; and the cleaning liquid is supplied on the bottom surface of the covered rotary cup, while rotating the covered rotary cup at a third rotational speed smaller than the first rotational speed, wherein the speeds may be set in such a manner that, for example, the first rotational speed is in the range of from 350 to 650 rpm, the second rotational speed is in the range of from 700 to 1300 rpm and the third rotational speed is in the range of from 14 to 26 rpm.
According to the present invention, in a condition that the covered rotary cup is continued to rotates, the cleaning liquid is supplied toward the rectifying plate from the middle of the cover of the rotary cup and at the same time the cleaning liquid is supplied on a lower surface of the outer peripheral portion of the rectifying plate, the inner side surface of the covered rotary cup and the bottom of the stationary cup and thereby the cleaning liquid supplied from the middle of the cover of the rotary cup is sprayed outwardly by a centrifugal force caused by the rotating rectifying plate to remove a coating liquid adhered on the lower surface of the cover, and the coating liquid adhered to the lower surface of the outer peripheral portion of the rectifying plate, the inner side surface of the rotary cup and the bottom surface of the stationary cup is removed by the cleaning liquid directly supplied thereto.
Besides, the coating liquid adhered on a lower surface of the outer peripheral portion of the rotary cup and the inner side surface of the stationary cup can be removed by supplying the cleaning liquid thereon. In this case, the lower part of the inner side surface of the stationary cup can be formed in such a manner that the inner side surface of the stationary cup is bent outwardly and thereby there can be produced a stagnant space of an air stream flowing a gap between the rotary cup and stationary cup, so that the coating liquid is held up in the stagnant space and prevented to flow back upwardly. Moreover, the coating liquid adhered on the stationary cup can be removed by supplying the cleaning liquid from the third nozzle toward the bent portion of the inner side surface of the stationary cup.
When the cleaning liquid is supplied toward the rectifying plate from the middle of the cover of the covered rotary cup, while rotating the covered rotary cup at the first rotational speed, for example in the range of 350 to 650 rpm, the cleaning liquid is forced impinge on a lower surface of the outer peripheral portion of the cover by an centrifugal force caused by a rotation of the rectifying plate which rotates together with the rotary cup and thereby the coating liquid adhered on the lower surface of the cover can be removed. When the cleaning liquid is supplied toward a lower surface of the outer peripheral portion of the rectifying plate and the inner side surface of the covered rotary cup while rotating the covered rotary cup at a rotational speed, for example in the range of 700 to 1300 rpm, the cleaning liquid can be supplied with a good efficiency over a broad surfaces covering the lower surface of the outer peripheral portion of the rectifying plate and the inner side surface of the rotary cup. When the cleaning liquid is supplied on the bottom surface of the covered rotary cup and a target area of a stream thereof is moved from the middle to the outer peripheral, while rotating the covered rotary cup at a rotational speed, for example in the range of 14 to 26 rpm, the coating liquid adhered on the bottom can be removed.
Additional objects and advantages of the invention will be set forth in the description which follows and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and combinations particularly pointed out in the appended claims.